Introduction: Bariatric surgery is an effective treatment for morbid obesity and metabolic syndrome, including type 2 diabetes mellitus. However, metabolic complications such as diabetic and starvation ketoacidosis may occur in the perioperative period, particularly in patients with reduced oral intake, rapid weight loss, and altered insulin requirements. Case: A 37-year-old male with type 2 diabetes mellitus, hypertension, dyslipidemia, and morbid obesity (body mass index 60 kg/m²) was referred for bariatric surgery. Preoperatively, he was initiated on subcutaneous semaglutide 1 mg weekly for weight optimization, resulting in weight loss from 178 to 127 kg. His hemoglobin A1c was 9.5%. He subsequently underwent laparoscopic proximal jejunal bypass sleeve gastrectomy on 5 November 2025. Two weeks postoperatively, he reported lethargy and was clinically found to be dehydrated, following poor tolerance of nourishing fluids and inadequate caloric intake. Capillary blood glucose was 7.6 mmol/L. Investigations revealed metabolic acidosis with markedly elevated serum ketones (4.9 mmol/L), consistent with ketoacidosis. He was commenced on an intravenous insulin infusion and aggressive IV fluid resuscitation. Attempts to discontinue insulin infusion resulted in recurrent ketoacidosis, attributed to poor tolerance of nourishing fluids. Following multidisciplinary input involving endocrinologists, a diabetes educator, and a dietitian, he was able to tolerate enteral nutritional supplementation. Insulin infusion was successfully discontinued, and he was discharged on a basal bolus subcutaneous insulin regimen. Conclusion Ketoacidosis following bariatric surgery is an underrecognized complication and may occur even in patients with type 2 diabetes mellitus and relatively normal blood glucose levels. Contributing factors included prolonged caloric deprivation, rapid weight loss, postsurgical catabolic state, and relative insulin deficiency. Recently used glucagon-like peptide-1 receptor agonist may have further suppressed appetite, compounding postoperative nutritional intolerance. The involvement of a multidisciplinary team, including endocrinologists, a dietician, diabetic educators, and surgical teams, is essential to optimize outcomes and prevent severe complications.
Bariatrics